From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E25B0C32750 for ; Fri, 2 Aug 2019 09:31:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B31D12183F for ; Fri, 2 Aug 2019 09:31:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564738307; bh=kQtS5HRnJ8psTEGIU5vV0Utd3m2MptNrHxxPF7SjCPU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=UhT0L7PzPlNsWXrLGxEvqvcrheQB/qIG6U8Gr5hF+8nC0bfzsuWRaGF1SDqqnmKNm JeZGxZCfDobn4O4hyFOBEyOP2XFMW860Nswhlq6tcjOL6lCF03hcnsZTuDb9Pi3Gws CzmpsWlooea9D2+F2vrDji5YCWfW1Gg+qs/TU8+8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404746AbfHBJbq (ORCPT ); Fri, 2 Aug 2019 05:31:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:58102 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404734AbfHBJbn (ORCPT ); Fri, 2 Aug 2019 05:31:43 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6B1CE21783; Fri, 2 Aug 2019 09:31:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564738302; bh=kQtS5HRnJ8psTEGIU5vV0Utd3m2MptNrHxxPF7SjCPU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=V1zS0xr/sE6i4ye0rOdA7KTCvK5jrvSZenpMaBFDveBAIXS/FlmBCIfjGKctzEt+U qlhKenw/pSvGQ1wcbXeU7v5bQ8bozvdFiYva4Z0e2PZyVPvIupIER3aUNGYwr7dnu3 JCjpmVFDvQfpGEo0nnQ2XTy12w84B6+kT/8zTdF0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jason Wang , "Michael S. Tsirkin" , "David S. Miller" , Sasha Levin Subject: [PATCH 4.4 034/158] vhost_net: disable zerocopy by default Date: Fri, 2 Aug 2019 11:27:35 +0200 Message-Id: <20190802092210.747925084@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190802092203.671944552@linuxfoundation.org> References: <20190802092203.671944552@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 098eadce3c622c07b328d0a43dda379b38cf7c5e ] Vhost_net was known to suffer from HOL[1] issues which is not easy to fix. Several downstream disable the feature by default. What's more, the datapath was split and datacopy path got the support of batching and XDP support recently which makes it faster than zerocopy part for small packets transmission. It looks to me that disable zerocopy by default is more appropriate. It cold be enabled by default again in the future if we fix the above issues. [1] https://patchwork.kernel.org/patch/3787671/ Signed-off-by: Jason Wang Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/vhost/net.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 645b2197930e..f46317135224 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -30,7 +30,7 @@ #include "vhost.h" -static int experimental_zcopytx = 1; +static int experimental_zcopytx = 0; module_param(experimental_zcopytx, int, 0444); MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;" " 1 -Enable; 0 - Disable"); -- 2.20.1